1. INFN, Department of Physics, University of Rome, “Tor Vergata” Via della Ricerca Scientifica 1, 00133 Rome, Italy
2. Instituto de Química y Bioquímica Facultad de Ciencias, Universidad de Valparaíso, Avenida Gran Bretaña, 1111 Playa Ancha, Valparaíso, Chile
3. Centro S3, Istituto Nanoscienze-Consiglio Nazionale delle Ricerche (CNR-NANO), Via Campi 213/A, 41125 Modena, Italy
4. Department of Civil and Environmental Engineering (DICA), The University of Perugia, Via G. Duranti, 93, I-06125 Perugia, Italy
5. CNR-ISTM, 06123 Perugia, Italy